ldgen: allow + sign in archive names

Closes https://github.com/espressif/esp-idf/issues/8073

tools/ldgen/test/test_fragments.py

@@ -1,19 +1,9 @@
 #!/usr/bin/env python
 #
-# Copyright 2021 Espressif Systems (Shanghai) CO LTD
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
+# SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: Apache-2.0
 #
+
 import os
 import sys
 import tempfile
@@ -682,6 +672,18 @@ entries:
         with self.assertRaises(ParseFatalException):
             FragmentFile(test_fragment, self.sdkconfig)
 
+    def test_archive_allowed_names(self):
+        test_fragment = self.create_fragment_file(u"""
+[mapping:test]
+archive:
+    libstdc++.a
+entries:
+    * (default)
+""")
+
+        fragment_file = FragmentFile(test_fragment, self.sdkconfig)
+        self.assertEqual('libstdc++.a', fragment_file.fragments[0].archive)
+
     def test_empty_entries(self):
         test_fragment = self.create_fragment_file(u"""
 [mapping:test]